Not all dukes are royal, in the UK for instance there are a few non-royal dukes.... not sure whether the Duke of Cleve was considered royalty though...

They are not royal, the 26 Dukes but part of the peerage. There are also royal dukes, because usually when a Monarch's son reached maturity or married he was given a royal dukedom as a mark of status as William was.

In my opinion Anne of Cleves is the most fortunate of Henry VIII wives....untouched, unharmed and heartily rewarded in the bargain...she might have had an empty bed but she also had her head, her reputation and a good place to live as she saw fit...not too bad in all...Henry acted as the pig he was..none of the women are really to be blamed, except perhaps for the Anne of Bolyen however her scheming father, Thomas, may have provided her the idea and backing.....Catherine of Aragon really showed her metal and really took on life...my hat is off to her...but my vote is for Anne of Cleves...who outlived all by ten years....

But the question is who is one's favourite...
Anna of Cleves was lucky up to a point, but it wasn't an ideal situaiton for her. She was comfortably off, but stuck in England, and unable to marry or have a family. And in later years I htink she was more discontented.. it is said that she hoped she migt remarry Henry when he got rid of Kat Howard.

Technically Anne was free to marry again five years later. She would have lost her home and her annual annuity if she did, but she could. The only thing stopping her remarriage sooner was the fact she was considered to be married. The annulment was granted on the Wrong assumption that she was pre-contracted to Francis of Lorraine. This was considered as good as married. Francis died in 1545 (annulment in 1540). Francis himself had married one of the other candidates Henry had in mind, Christina of Denmark. Christina who was a sixteen year old widowed duchess of Milan at the time is reported as saying if she had two heads, one would be at Henry's disposal. Christina and Francis had four children and she served as regent for his heir.

Anne was said to be much happier in England. Her life under her brother's rule was said to have been quite unhappy. In England she was her own mistress. Yes there is talk there was a move for her to remarry Henry but it seemed more her brother's scheming then her own. She made quite a happy life for herself, close to her stepchildren.